The present invention is directed to a palladium-based catalyst system comprising an aqueous solution of a derivative of palladium and of a water-soluble ligand associated with a nitrile, and the use of the palladium-based catalyst system in organic chemistry in reactions employing palladium-based catalysts, and more particularly, in nucleophilic substitution reactions.
Nucleophilic reactants have been reacted with allyl derivatives such as cinnamyl acetate or with geranyl acetate in the presence of catalysts selected from palladium complexes optionally in the presence of ligands such as triphenylphosphine [J. Tsuji, Tetrahedron, 42, 4361-4401 (1986)]. Reactions of telomerization of dienes with compounds containing mobile hydrogen (FR 2,366,237, EP 287,066) or carbonylation reactions [J. Kiji et al., Chem. Letters, 957-960 (1988)] using catalysts consisting of a transition metal associated with a soluble phosphine have been performed. However, the use of these processes does not make it possible to separate the reaction products easily from the catalyst, which is soluble in the organic solvents employed. Accordingly, the separation of the reaction products is difficult, and furthermore, the catalyst cannot be recovered easily and recycled.
It has now been found according to the catalyst system of the present invention that a catalyst comprising an aqueous solution of a palladium derivative and of a water-soluble ligand, associated with a nitrile, can be easily separated from the reaction products and easily recycled.